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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 1000px;
            height: 1000px;
            background-color: lawngreen;
            flex-wrap: wrap;
            /* align-content: center;----------在侧轴中间显示 */
            /* align-content: flex-end;--------在侧轴尾部开始排列 */
            /* align-content: flex-start;------默认值 在侧轴的头部开始排列 */
            /* align-content: space-around;----子项在侧轴平分剩余空间 */
            /* align-content: space-between;---子项在侧轴先分布在两头，再平分剩余空间 */
            /* align-content: stretch;---------设置子项元素高度，平分父元素高度 */
        }
        span {
            width: 210px;
            height: 210px;
            background-color: lightcoral;
            margin: 10px;
        }
    </style>
</head>
<body>
    <div>
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    </div>
</body>
</html>